This invention relates to an interlock for aligned switches, and more particularly to an interlock that prevents two aligned switches from both being in the ON position at the same time, such as in an application in which an electrical panel is capable of being supplied with power from either a primary or a secondary source of power. Interlock arrangements are commonly employed in an electrical supply system which is capable of having power supplied from two different sources. Illustratively, an electrical panel or other power distribution device may be interconnected with a primary source, e.g. an electric utility, as well as a secondary power source, such as an electrical generator, so as to enable power to be supplied in the event of an interruption in the primary power source. Each power source is interconnected with a switch for controlling the supply of power to the electrical panel or other power distribution device. The interlock arrangement ensures that the switch connecting the secondary power source is not in the ON position when an aligned switch connecting the primary power source is in the ON position, and vice versa. An example of an interlock of this type is shown and described in Flegel U.S. Pat. No. 6,031,193, the disclosure of which is hereby incorporated by reference.
In a typical installation, the pair of aligned switches are engaged in a cabinet or the like, which includes a power supply contact member with which the switches are engaged. The cabinet further includes a mounting arrangement for maintaining the switches in position within the cabinet and in engagement with the contact member. Typically, the switches can be individually engaged with the contact member and removed from the contact member.
It is an object of the present invention to provide a switch interlock arrangement which functions to ensure that two adjacent, aligned switches cannot both be in the ON position at the same time, and which is operable to prevent disengagement of the switches from the power supply contact member. It is a further object of the invention to provide such an interlock arrangement which does not require any alteration or modification of the existing structure of the switches or the mounting arrangement by which the switches are engaged within the cabinet with the contact member. It is another object of the invention to provide such an interlock arrangement which is relatively simple in its components, construction and installation, yet which is highly effective to provide both an interlock function and to maintain the switches in engagement with the contact member. Yet another object of the invention is to provide such an interlock arrangement which can be removed and replaced relatively easily, when it is desired to remove one or both of the switches. It is a further object of the invention to provide such an interlock arrangement which provides similar operation as prior art interlock arrangements which have proven performance and construction.
In accordance with the present invention, a pair of switches, such as may be interconnected with separate sources of electrical power, are engaged with an electrical contact member associated with an electrical panel or the like. The switches are aligned with each other, and include operating members movable between ON and OFF positions. Each switch includes a switch body to which the operating member is mounted for movement between the ON and OFF positions, and the switch body is engaged with a mounting arrangement associated with the electrical panel or the like, and with the electrical contact member. Each switch operating member includes an actuator portion spaced outwardly from a surface defined by the switch body. An interlock arrangement is adapted to interact with the actuator portions of the switch operating members, and is configured to prevent the operating members from being in the ON position at the same time. In addition, the interlock arrangement is configured to prevent disengagement of the switch bodies from the mounting arrangement and movement of the switch bodies out of engagement with the contact member.
The interlock arrangement is preferably in the form of an interlock base member which is placed between the outer actuator portion of each operating member and the outwardly facing surface of the switch body from which the outer actuator portion is spaced, such that the interlock base member is located within an opening defined by each switch operating member.
A pair of inner engagement members are secured to the interlock base member between the switch operating members. The inner engagement members are spaced apart from each other, and are located and arranged so as to engage the outer actuator portions of the operating members as one or the other of the operating members is moved to its ON position, to ensure that the other operating member is in its OFF position.
The interlock arrangement further includes a pair of outer engagement members, each of which is located outwardly of the outer actuator portion of one of the operating members. In this manner, each outer actuator portion is located between one of the inner engagement members and one of the outer engagement members.
The interlock base member overlies adjacent edges defined by the switch bodies when the switch bodies are in engagement with the mounting arrangement and with the electrical contact member. In the event an outward force is applied to one or both of the switch bodies, the interlock member functions to engage the edges of the switch bodies. The outer engagement members are moved into contact with the outer actuator portions of the operating members, so as to provide a binding action which prevents disengagement of the switch bodies from the mounting arrangement and from the electrical contact member.
The inner engagement members are preferably engaged with the interlock base member subsequent to insertion of the interlock base member through the openings defined by the switch operating members. In one form, the inner engagement members have a common mounting section therebetween, which is provided with a pair of openings. Threaded fasteners extend through the openings into engagement with aligned threaded openings formed in the interlock base member, to secure the mounting section to the interlock base member. Similarly, one or both of the outer engagement members may be interconnected with a mounting section which is adapted to be secured to the interlock base member via one or more fasteners.
The present invention further contemplates a retainer arrangement for preventing inadvertent removal of the threaded fasteners that secure the inner engagement members to the interlock base member. The retainer arrangement is preferably in the form of a movable retainer member which is movable between an engaged position and a release position. When the retainer member is in its engaged position, the retainer member overlies and engages the threaded fasteners so as to prevent outward movement of the threaded fasteners, and thereby to prevent the inner engagement members from being inadvertently disengaged from the interlock base member. In its release position, the retainer member is configured to expose the fasteners, so as to enable the inner engagement members to be removed in the event it is required to remove the interlock arrangement so as to service or repair one or the other of the switches.